This post is not about why wasps themselves would hibernate over winter. The reasons are fairly obvious: It's cold, and there's not enough food around to survive. (Incidentally, it's only the new queen wasps that hibernate, after they have mated with the ephemeral males - who are only alive for a matter of days, their only job being to mate and then die)

No, this post is about why a person would want to actively 'hibernate' a wasp over winter. Or, even, thousands of wasps.

To explain this, I've uploaded some pictures that explain the process of hibernating a wasp. And then, a couple of paragraphs on the presumed effects that this has on the ecosystem, particularly in the context of a community with a penchant for wasp larvae. Combined, I hope that this gives a good answer to the question 'Why hibernate?' - In short, what comes around goes around, and if you want wasps next year, well, you'd better hibernate a few this year.

The pictures below explain the hibernation process. (Written explanations pop up when you move the mouse over each picture)

So, why go to all this trouble? Because in an area where people scour the landscape for wasp nests in both the spring and autumn seasons, and then harvest these nests before the mating season, there's quite a high possibility that this will lead to a depletion in the wasp population the following year.

Therefore, by keeping a few nests aside, ensuring that the conditions are conducive to mating and hibernation, and then keeping the hibernating queens in protected conditions throughout the winter months, one ensures that there will be queen wasps who survive until the spring.

In this way, the wasp population (and therefore the forest ecosystem as a whole: As insect predators and flower pollinators, wasps are an essential part of the ecosystem) is maintained, year after year - and people are still able to enjoy the annual harvest of hachi-no-ko!

Some people paid me to give a talk! So, I decided to make good use of the proceeds, to make up for the time I spent not sleeping and preparing for said talk... and I went to visit my friend in Kyushu, the most southerly of the four main Japanese islands.

Kyushu is WARM. I mean, it's 9 degrees, rather than minus 3 degrees.

And, it has a jungle onsen. Which is obviously a brilliant concept. But it gets even better: The jungle onsen isn't just a steamy greenhouse full of jungle plants and warm sulphuric hot spring baths, it even has a SLIDE. Too many capitals, I know - but really, a stone slide into a hot spring bath?? In a jungle? Without going to an actual jungle, I don't think it gets much better than this.

Since it's not actually permitted to take photos of onsen, this is really not a great image, taken surreptitiously through a steamy window...but you get the idea

On to the more serious stuff. Namely, strawberries and honey. Is there a connection there? Apart from both being sweet and delicious..yes, there is. Keep bees amidst your strawberry plants, and you won't only increase your yield but you'll also be able to produce strawberries that have a better shape to them.

Why? Because the bees pollenate the strawberry plants. 'Bees are the key to good strawberries', according to the owner of a fruit farm in Kyushu, where a single hive of honeybees is used to pollenate each greenhouse, and they are able to harvest their strawberries right through from December until May.

The fruit farm also had an adjoining shop/cafe/restaurant, serving unlikely seasonal-fruit-filled dishes such as persimmon pasta and apple pizza, all served amidst the scent of warm apple pie baking in the background.

I have unwittingly become a great fan of cooking with dried caterpillars.

When I first tasted caterpillars in DRC, I thought they were delicious, but I was also pretty sure that they didn't have much potential as an ingredient that could be enjoyed anywhere but the middle of a tropical rainforest for a very short period of time. Caterpillars are seasonally abundant, and everyone was adamant that they had to be enjoyed fresh. You could dry them, but...it just wasn't the same.

However, it turns out this really isn't the case with the dried caterpillars I brought back with me from Zimbabwe. Gonimbrasia belina and Gynanisa maia, popularly known as Mopane Worms (but with a whole host of other local names differing according to place and species - madora, macimbi, gandari, pipi, etc), rehydrate very nicely. I think I am beginning to understand why several tonnes of them are imported to France and Belgium every year.

But what I dont understand is why, for the UK consumer, your only option is to buy 'salted-and-ready-to-eat' mopane worms in a can from Selfridges, at the insane price of £14.99 for 40g.

Go to a market in Zimbabwe with a $1 note and your average mopane worm seller will pour 150-200g of dried worms into a bag for you. To rehydrate them, you just soak them in hot water for a few hours, and they are ready to be cooked. And the cooking process is brilliant: Add any or all of your favourite flavourings and vegetables. Simmer, slowly. The caterpillars add a savoury, smokey, rich taste to the stew, and their texture is so unique that it gives an interesting contrast to whatever vegetables you have decided to use. The women in the Zimbabwean markets who explained this to me recommended tomatoes, onions, garlic, greens, chillis, and salt as their go-to ingredients.

Since being back in Japan I've tried a few experiments, and from my mistakes I've learnt two things so far:

1) Frying is just not worth it. They lose their flavour and texture. 2) Flavour-wise, they do go well with Japanese condiments (soy sauce, ginger, mirin), but you have to be careful about the process. I added mirin at the very beginning of the cooking process and I've been taught since that this is a mistake. The sugar content in the mirin will cause the skin of the caterpillar to harden. Mirin and/or sugar should only be added at the very end, to taste.

The dish above was an experiment - I cooked the caterpillars with garlic, chilli and bay leaves to soften them and add flavour. Then my friend sauteed them with vegetables, and topped this with salad. This also worked really nicely and yes, the whole dish was eaten in one lunchtime!

The dish below was another experiment, this time inspired by a ridiculous amount of freshly brewed sake. I simmered the caterpillars with onion, tomato, garlic, paprika, bay leaves and smoked tofu. Just before serving, in order to preserve the taste of the stock that is created by simmering the caterpillars, I mixed in a couple of eggs.

And last night we enjoyed some very unique insect dishes, cooked by a professional Japanese chef, using fresh insects brought over on the plane from Zimbabwe the day before! Here they are:

Squid and termite ceviche

Tofu-termite croquettes

Caterpillar and onion omelette

They were delicious, and all very protein-rich, as each contained a second protein source to complement the insect protein. This was perfect in context - these dishes were served as we sat drinking and talking for several hours, so they were an ideal accompaniment.

However, in Zimbabwe, caterpillars are usually used as a stand-alone protein source in meals, accompanied by leafy vegetables and carbohydrate-rich maize meal or rice.

So, that'll be the next challenge: A Japanese-style main dish in which caterpillars are the main protein source. Might give it a go tomorrow..

(I nearly forgot, drinks-pairing is obviously crucial: The squid and termite ceviche would go nicely with a dry white; Tofu-termite croquettes are a beer-drinker's snack, and the caterpillar and onion omelette is an end-of-the-night dish, an alternative to a kebab-and-chips, but one which you wont regret nearly as much the morning after)

I came to Zimbabwe hoping to find out more about the use of insects as wild indigenous natural resources: Termites, caterpillars, bees, and all sorts of other invertebrates. And I've seen and learnt all sorts of things! But in the process I also learnt a bit about some other interesting and unexpected natural resources. So I thought I'd write a brief overview of what I found out:

But recently, the health food market in the United States has discovered spirulina. It is said to have 'antioxidant properties' and the powder is compressed into supplement pills and sold at high prices. So where does Zimbabwe come into this? Well, in Southeastern Zimbabwe, efforts are currently underway to develop methods of cultivating spirulina in the laboratory for high yields that could one day result in the construction of a spirulina processing plant, bringing a new source of income to a country with fairly low import rates.

Jatropha

Jatropha is a plant indigenous to the Americas, but now found 'throughout the tropics' (1). It is not eaten by animals due to toxicity levels and therefore used as a 'living fence' against animal crop damage in some countries (1), but in Southeastern Zimbabwe it is being cultivated for oil production.

The oil that is produced from the Jatropha seed can be used for biofuel, and was originally celebrated as a novel and environmentally friendly solution to an impending global energy crisis, as Jatropha grows well even on unfertile, sandy soils. However, growth rates and seed production rates fell way below expectations, and Jatropha is no longer favoured for biofuel production (2).

Instead, in Southeastern Zimbabwe, the oil of the Jatropha seed is being used to make soap.

Is this viable? The sap of the tree is said to be a skin irritant, and the seeds contain high levels of toxic compounds, yet I was told that the soap has skin-softening properties... I was given a sample, so I'll give it a try. But given the propensity of small children for trying to eat soap (when ingesting just three of the Jatropha seeds can kill a human adult), I think its future as a product will depend heavily on what further research has to say about health and safety issues!

Fish guts

Now here's an even more unlikely source of ... soap.

Every year, thousands of metric tonnes of freshwater tilapia are harvested from the Kariba dam in Zimbabwe. These fish are gutted before they are sold on the market, and usually the innards are simply discarded. However, waste products are called waste products for a reason - they could be utilised in some way, it's just a case of figuring out how.

A quick internet search tells me fish guts are, like Jatropha above, a potential source of biofuel. This fish farm in Honduras is one really interesting example of this.

But in Zimbabwe, as with Jatropha seeds, people are trying out a new use for the oil produced from fish waste: Soap!

The best thing about this soap is that it smells like fish. Just like fish. Fortunately chemists have recently discovered a method of neutralising the smell, though it's yet to be patented, so it'll be a while before fish gut soap is on the market. The current product really does smell very, very fishy. Again, I was lucky enough to be given a sample of this very unusual soap. But I'm not sure I'll be trying it out... in fact the reason I haven't uploaded a photo is because the thought of unwrapping it from its layers of plastic to take said photo, and consequently releasing the smell at this time in the morning, makes me feel a bit sick..

Anyway, if there's one thing that I've learnt from all of this, it's that thinking up innovative ways of using 'waste' products can be profitable, disastrous or hilarious - but never boring. And it's probably always worth giving things a go. Which is why after finding out all sorts of things about mopane caterpillars, I reckon the next big thing might well be 'mopane tea'...any guesses as to how this can be made?

'Mopane Worm' is the name given to the larvae of the emperor moth Gonimbrasia belina, and it forms probably the largest edible insect industry in the world.

Every year an estimated 95 billion mopane worms are processed and sold in Southern Africa, with an annual turnover estimated at $85 million. The caterpillars are specialists of the mopane tree Colophospermum mopane, which is found in abundance in many areas of Southern Zimbabwe. Here are some pictures of the various life cycle stages of Gonimbrasia belina, and its feeding tree:

The caterpillars are found dried in markets across the country, alongside other protein sources such as beans, soya protein and dried fish:

They are even found in supermarkets, fried in oil with seasonings (usually chilli and salt) and ready-to-eat:

The dried caterpillars are easy to transport and sold fairly cheaply, so I'm planning on taking lots back to Japan with me! (Yes, it's legal - Though sadly not allowed through UK customs..)